A Polyphenol Rich Muscadine Grape Extract Reduces Triple Negative Breast Cancer Cell Migration in Association with Changes in Cell Morphology and Motility-Related Proteins

Abstract

Abstract Objectives Triple negative breast cancer (TNBC) is a subtype of breast cancer characterized by the lack of estrogen receptors, progesterone receptors and over-expression of the human epidermal growth factor receptor 2, limiting targeted treatment. TNBC disproportionally affects ethnic minorities and younger women and has a high propensity to metastasize, often within 5 years of diagnosis, making it one of the most aggressive breast cancer subtypes. We showed that treatment with a proprietary muscadine grape extract (MGE) reduced the growth and metastasis of TNBC in mice. Muscadine grapes (V. Rotundifolia) are rich in polyphenols and extracts produced from muscadine grape seed and skin are marketed as nutraceuticals for their anti-oxidant, anti-inflammatory, and anti-cancer properties. The goal of these studies was to determine the molecular mechanisms for the reduction in metastatic growth by MGE. Methods A proprietary extract was prepared from muscadine grape seeds and skins. Migration of MDA-MB-231 and BT-549 cells was measured by a scratch wound assay, cell shape was visualized by confocal microscopy and mRNA/proteins that participate in cell migration/motility were measured by RT-PCR and western blot hybridization. Results The extract reduced the migration of MDA-MB-231 and BT-549 TNBC cells in a dose-dependent manner. The reduction in cell migration was associated with MGE-induced alterations in cell shape and actin filament organization, visualized by confocal microscopy. The extract caused an apparent loss of cell polarization in MDA-MB-231 cells and a reduction in the presence of filopodia in BT-549 cells. The MGE-induced reduction in migration and alterations in cell shape and polarization were associated with a decrease in Rho kinase ROCK1/2 mRNA and protein as well as both the mRNA and protein expression of RHAMM, a protein that is implicated in both cell motility and breast cancer progression. Conclusions These results demonstrate that a proprietary MGE reduces TNBC cell migration, in association with changes in cell shape and cytoskeleton as well as proteins that regulate migration and motility, suggesting that treatment of TNBC patients with MGE may slow or prevent metastatic progression. Funding Sources Chronic Disease Research Fund.